Metallic Nanoparticles and Carbon-Based Materials for the Fabrication of Electrochemical Biosensors aiming the Mycotoxin Analysis in Food

Alexandre L. B. Baccaro, Poliana Cardoso, Roberta H. Piccoli, Tatiana C. e Bufalo, Roberta C. Martins, Thaina M. Vilela, Ana Carolina F. Alves, Laíse N. S. Pereira, Fabiana S. Felix

Abstract: Mycotoxins are low molecular-weight compounds produced by fungi genera as secondary metabolites during pre- and post-harvest storage of crops and foodstuff. Many reports show highly concerning issues ascribed to their carcinogenic, genotoxic, immunosuppressive, and teratogenic properties. Biosensors are compact analytical devices incorporating a biological or biologically-derived recognition element that might be either integrated within or intimately associated with a physicochemical transducer. The most applied bioreceptors are the enzymes (biosensors), DNA and RNA nucleic acids (genosensors), antibodies (immunosensors), aptamers (aptasensors) or living cells (microbial biosensors). The integration of nanotechnology to the biosensors field brought sensitivity and versatility for bioassays, since nanomaterials might play the role as new signal markers, surface subtracts for functionalization and fixation of biomolecules, and generation source of analytical signals. For electrochemical biosensors, nanostructures can enhance the sensitivity of electrochemical techniques by filling the gap between the converter and the biorecognition element. Metal nanoparticles are used to improve the analytical sensitivity by refining the electrical connectivity of the interface, increasing both the chemical accessibility of analytes and the sensing surface with higher amounts of bioaffinity recognition sites. Gold nanoparticles are among the most used nanostructures due to its unique electrocatalytic activity and conductivity. In turn, carbon-based nanomaterials are very appealing considering their large specific surface area and high electron transfer rates. Carbon nanotubes (CNTs) and graphene oxide materials are the most employed carbon-based materials. There is no doubt that the whole bioassay has become more versatile, robust, and dynamic with the introduction of the nanoscience, consolidating in an emerging field with current intense research. Hence, this work reviews some selected applications of electrochemical metallic and carbon-based nanobiosensors for the determination of mycotoxins in food, revisiting important fundamentals of the electrochemical bioassay.

Development and Validation of a Stability-Indicating High-Performance Liquid Chromatography with Diode-Array Detection Method for Oclacitinib Using Analytical Quality by Design Approach

Dalton A. de Souza, Danilo R. O. Momade, Allan M. Junkert, Alexandre F. Cobre, Dile P. Stremel, Raul E. L. Lazo, Luana M. Ferreira, Roberto Pontarolo

Abstract: This study aimed to develop and validate a stability-indicating method by high performance liquid chromatography to quantify the Oclacitinib (OCLA), on the presence of its degradation products (DPs), by applying Analytical Quality by Design (AQbD) strategy. underwent exposure to acid, alkaline, neutral, photolytic, oxidative, and thermal stress conditions, with degradation products observed under acidic and photolytic conditions. After defining the Analytical Target Profile, the tailing factor, peak purity, and last peak retention time were established as Critical Quality Attributes. The risk assessment led to the designation of the mobile and stationary phases, the oven temperature, the injection volume and the flow rate as Critical Method Parameters. A screening step was then performed to select categorical variables, and the significant factors were subsequently incorporated into the Box-Behnken Design for method optimization. The optimized method was achieved using Zorbax XBD C18 column (150 x 4.6 mm, 3.5 μm), oven temperature 17 °C, and injection volume 25 µL. The mobile phase consisted of ammonium formate buffer 100 mM, pH 3.1 and methanol, and a flow rate of 1.1 mL min^-1, eluted by a stepwise gradient. Furthermore, the method demonstrated excellent selectivity and linearity (R> 0.999). The theoretical limit of detection was determined to be 5.52 µg mL-1, while the theoretical limit of quantification was found to be 16.74 µg mL^-1. Furthermore, precision and accuracy were demonstrated with a relative standard deviation below 2.0% and accuracy ranging from 99.87% to 101.38%. Hence, the method was successfully developed, optimized, and validated by applying AQbD approach, becoming a useful methodology for routine quality control of OCLA and its degradation products.

Geochemical Hydrocarbon Markers in River Sediments from a Densely Populated Area of Curitiba, Brazil

Lucélia Taverna, Fabricio Augusto Hansel, Cesar Alexandro da Silva, Vânia Ribeiro Ferreira, Emerson Luís Yoshio Hara, Rafael Garrett Dolatto, Marco Tadeu Grassi

Abstract: Employing geochemical hydrocarbon markers, this work aimed to identify the sources of organic matter in water bodies in the Metropolitan Region of Curitiba, State of Paraná, Brazil. Also, a reduced scale protocol assisted by ultrasonic bath was developed and applied to extraction, fractionation, and clean-up of the aliphatic hydrocarbons (AH), polycyclic aromatic hydrocarbons (PAH), and sterols in sediment samples from the rivers Barigui, Iguaçu, and Timbu and from the water supply reservoirs Iraí and Passaúna. The total concentrations determined in all samples ranged from 1.15 to 509.65 µg g^-1for AH, between 97.3 and 440.65 ng g^-1 for PAH, and from 1.73 to 747.92 µg g^-1 for sterols. The highest concentration of the three markers was observed at the Timbu River, which is in an environmental protection area. About the samples from the Barigui River and both reservoirs, more than 95% of the molecules were classified as natural input. On the other hand, in the samples from the Iguaçu and Timbu rivers, densely urbanized area rivers, 53% and 88% of the markers, respectively, were classified as of anthropogenic origin. However, the ratios for PAH revealed the combustion of biomass as the main source of these compounds. The fecal marker coprostanol, which was detected in both the Iguaçu and Barigui rivers, shows contamination by domestic and industrial sewage, respectively. The ratios for sterols showed the presence of domestic sewage in rivers and reservoirs close to expanding urban areas. Thus, it was possible to conclude that the uncontrolled expansion of cities and their activities can compromise the integrity of the water bodies, their biota, and the supply of the population.

Vortex-Assisted Liquid-Liquid Microextraction Based on Hydrophobic Deep Eutectic Solvent for Nickel Determination in Water Samples by Smartphone Digital Image Colorimetry

Airton Vicente Pereira, Orlando Fatibello-Filho, Geovanna Morgado da Penha, Emily Amábile Tavares

Abstract: An environmentally friendly and sensitive vortex-assisted liquid-liquid microextraction (VALLME) method using a hydrophobic deep eutectic solvent (HDES) coupled with smartphone-based digital image colorimetry (SDIC) was developed for the preconcentration and determination of trace nickel in electroplating wastewater. Nickel cations were complexed with dimethylglyoxime (DMG) to form a pink-red complex (Ni(DMG)₂). Some important factors, including the HDES type, pH, volume of solvent, dimethylglyoxime concentration, and vortex time, were investigated and optimized. The extraction was performed in 1 minute using 250 µL of HDES composed of tetrabutylammonium bromide (TBABr) with decanoic acid (1:2), with a sample volume of 10 mL at pH 8, and the image capture was made directly in the extraction tube without the need to separate the HDES phase. Under the optimum conditions, the method exhibited linearity within the concentration range of 0.45-5.9 mg L^-1, detection and quantification limits of 0.15 and 0.45 mg L^-1, and precision (RSD) of ± 2.6%. Application to water samples showed recoveries between 97% and 104%. The proposed HDES-based microextraction method offers an effective alternative for nickel determination in industrial wastewater.

Development of a Flow-Batch Analyzer for the On-Site Automated Determination of Residual Chlorine in Drinking Water

Guillermo Roth, Justina Medina, Moisés Knochen

Abstract: A novel automated analyzer for the determination of residual chlorine in water was developed and evaluated. The analyzer is based on the technique of flow-batch analysis and employs the DPD photometric method for measurement of free chlorine. To decrease complexity, a stirrer was not used for mixing, resorting instead to the turbulence of the fluids to attain a satisfactory mixing of the reactants. The prototype was built using peristaltic pumps, a reaction-detection cell, and an LED-photodiode detection system. The open-source Arduino microcontroller platform was used for data acquisition and control. The operational evaluation of the system included the study of the mixing process, the determination of the optimum concentration of DPD reagent and the calculation of analytical figures of merit: linear range, precision and accuracy of the results, as well as detection and quantification limits. The performance of the analyzer was deemed fit for the purpose of on-site analysis. This prototype is being taken as the basis for the design of an industrial-grade on-site on-line analyzer for the determination of residual chlorine in water treatment plants and drinking water distribution systems.

Sample Preparation Methods Focusing on Soy Biotechnological Samples: Towards Greener Application

João G. Veneziani Kamezawa, Lilian Seiko Kato, Elisânia Kelly Barbosa Fonseca, Marco Aurélio Zezzi Arruda

Abstract: Tissue and cell culture techniques have become pivotal in plant biotechnology, particularly for the improvement and mass propagation of economically important species such as soybean (Glycine max). Within this context, somatic embryogenesis has emerged as a powerful tool. Micronutrients like Fe, Mn, Mo, and Zn play essential roles in cellular metabolism and can serve as indicators of tissue growth and development. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is widely recognized for its sensitivity in multielement analysis at trace levels; however, sample preparation remains a critical and often resource-intensive step.

This study aims to develop and compare three distinct sample preparation methods for the determination of micronutrients in soybean calli using ICP-MS: (1) conventional acid decomposition, (2) acid extraction, and (3) acidless decomposition. The results indicated that all three methods provided statistically equivalent concentrations for all evaluated elements (p ≥ 0.05), with values ranging from 0.54 ± 0.08 µg g⁻¹ for Mo to 14 ± 1 µg g⁻¹ for Mn. Additionally, the residual chemical content (RCC) in the proposed methods was below the detection limit of 8 mg L⁻¹.

Sustainability assessment using the AGREEprep tool highlighted acidless decomposition as the most environmentally friendly method, primarily due to its use of greener reagents and higher sample throughput. These findings suggest that acidless decomposition presents a viable and sustainable alternative for micronutrient analysis in plant tissue culture applications.

48th RASBQ 2025: Brazilian Chemistry's Stage for Innovation and Collaboration

From June 8 to 11, 2025, Campinas, SP, hosted the 48th Annual Meeting of the Brazilian Chemical Society (RASBQ), the largest chemistry event in Latin America. The event included visits to the National Center for Research in Energy and Materials, highlighting laboratories such as the Brazilian Nanotechnology Laboratory and the Brazilian Synchrotron Light Laboratory. Key topics addressed included green chemistry, microplastics, chemical safety, innovation, and intellectual property.

Impurity Analysis of Gabapentin by HPLC-UV-CAD
Ruben Pawellek, Adrian Leistner, Ulrike Holzgrabe
Thermo Scientific

This application aims to replace the two separate compendial methods for the impurity analysis of gabapentin employed in the European Pharmacopoeia with one single HPLC method with hyphenated ultraviolet and charged aerosol detectors (UV-CAD). The complementary hyphenated detection techniques will enable the simultaneous detection of analytes with divergent physico-chemical properties. The UV-CAD method meets the required LOQs for a compendial application.

A Streamlined Laboratory Workflow for the Analysis of Common Contaminants according to the U.S. EPA 8270E and 8081B Methods using GC-MS/MS
Sarah Crumlett, Mark Belmont, Terry Jeffers, Adam Ladak, Giulia Riccardino, and Daniel Kutscher
Thermo Scientific

The goal of this application note is to demonstrate a modernized workflow for the analysis of semivolatile compounds and pesticide residues according to EPA 8270E and EPA 8081B methods using a single instrument platform based on gas chromatography coupled to triple quadrupole mass spectrometry (GC-MS/MS).

New Performance for High Volume Agriculture Laboratories
Milestone

Milestone's ETHOS UP equipped with the MAXI 24 High Performance (HP) rotor incorporates all of the benefits of closed vessel microwave digestion while making sample preparation fast, easy, effective, and of the highest quality. This innovative solution perfectly integrates with the powerfull ETHOS UP, matching both performance and throughput requirements of agricultural elemental analysis.

TSQ Altis Plus Triple Quadrupole Mass Spectrometer

With superior acquisition speeds, enhanced sensitivity, prototypical selectivity, and exceptional robustness, the Thermo Scientific TSQ Altis Plus mass spectrometer delivers unprecedented accuracy and precision for low-level compound detection and quantitation in complex matrices that redefines ultimate instrument performance.

Thermo Scientific TSQ 9610 Triple Quadrupole GC-MS/MS System

The TSQ 9610 system combines unstoppable robustness with the ability to change the GC column and clean the ion source without interrupting analytical workflows. When high sample throughput is essential, the system delivers results on time and with ease.

ETHOS UP High Performance Microwave Digestion System

Quality Analysis Starts with Great Sample Prep. The ETHOS UP™ fully embodies Milestone's philosophy in microwave sample preparation. Specifically designed for closed vessel microwave acid digestion, it offers productivity, safety, ease of use, connectivity, expertise and application flexibility.

Pittcon Conference & Expo

Pittcon is a friendly, welcoming environment where analytical chemists at all professional levels meet. Pittcon is a platform for sharing ideas and cooperating to form new ones. At Pittcon, you will find that spark that drives your research, your career, and above all, your scientific perspective forward.

SelectScience® Pioneers online Communication and Promotes Scientific Success

SelectScience® informs through trusted lab product reviews, virtual events, thought-leading webinars, features on hot scientific topics, eBooks and more, independent online publisher SelectScience® provides scientists across the world with vital information about the best products and techniques to use in their work.

CHROMacademy is the leading provider of eLearning for analytical science

For over 10 years, CHROMacademy has increased knowledge, efficiency and productivity across all applications of chromatography.